diff --git a/README.md b/README.md
index c74e2da..ed2345f 100644
--- a/README.md
+++ b/README.md
@@ -4,120 +4,8 @@ An express-like web server framework for Dart developers.
 
 ## Usage
 
-A simple usage example:
-
-```dart
-import 'package:dart_express/dart_express.dart';
-
-main() {
-  final app = express();
-
-  app.get('/', (req, res) {
-    res.json({
-      'hello': 'world',
-      'test': true,
-    });
-  });
-
-  app.listen(3000, (port) => print('Listening on port $port');
-}
-```
-
-Example with route parameters
-
-```dart
-import 'package:dart_express/dart_express.dart';
-
-main() {
-  final app = express();
-
-  app.get('/users/:userId/posts/:postId', (req, res) {
-    res.json({
-      'userId': req.params['userId'],
-      'postId': req.params['postId'],
-    });
-  });
-
-  app.listen(3000, (port) => print('Listening on port $port');
-}
-```
-
-With Body parsing Middleware:
-
-```dart
-import 'package:dart_express/dart_express.dart';
-
-main() {
-  final app = express();
-
-  app.use(BodyParser.json());
-
-  app.post('/post', (req, res) {
-    print(req.body);
-
-    res.send({
-      'request_body': req.body,
-    });
-  });
-
-  app.listen(3000, (port) => print('Listening on port $port');
-}
-```
-
-Using the mustache templating engine
-
-```dart
-import 'package:dart_express/dart_express.dart';
-
-main() {
-  final app = express();
-
-  app.use(BodyParser.json());
-  app.engine(MustacheEngine.use());
-
-  app.settings
-    ..viewsPath = 'custom_views_path'
-    ..viewEngine = 'mustache';
-
-  app.get('/', (req, res) {
-    res.render('index', {
-      'app_name': 'My Test App',
-    });
-  });
-
-  app.listen(3000, (port) => print('Listening on port $port');
-}
-```
-
-
-
-Listening to Https requests
-
-```dart
-  //listen for http requests
-  app.listen(port: 80, cb: (port) => print('listening for http on port $port'));
-
-  //assign certificate
-  var context = SecurityContext();
-  final chain = Platform.script.resolve('certificates/chain.pem').toFilePath();
-  final key = Platform.script.resolve('certificates/key.pem').toFilePath();
-
-  context.useCertificateChain(chain);
-  context.usePrivateKey(key);
-
-  //listen for https requests
-  app.listenHttps(
-    context,
-    port: 443,
-    cb: (port) => print('Listening for https on port $port'),
-  );
-```
-
-
+Check out the examples on [Github](https://github.com/deriegle/dart-express/tree/main/example).
 
 ### Currently supported View Engines
-
 - Basic HTML
-- Mustache
 - Markdown
-- Jael
diff --git a/example/api_routes.dart b/example/api_routes.dart
deleted file mode 100644
index 4704e2c..0000000
--- a/example/api_routes.dart
+++ /dev/null
@@ -1,82 +0,0 @@
-import 'package:dart_express/dart_express.dart';
-import 'package:meta/meta.dart';
-
-class User {
-  final int id;
-  final String email;
-
-  User({@required this.id, @required this.email});
-
-  Map<String, dynamic> toJson() {
-    return {
-      'id': id,
-      'email': email,
-    };
-  }
-}
-
-Router apiRouter() {
-  final router = Router();
-  final users = [
-    User(id: 1, email: 'test@example.com'),
-    User(id: 2, email: 'test2@example.com'),
-  ];
-
-  router.get('/', (req, res) {
-    res.status(200).json({
-      'hello': 'world',
-      'age': 25,
-    });
-  });
-
-  router.get('/users', (req, res) {
-    res.status(200).json({
-      'users': users.map((u) => u.toJson()).toList(),
-    });
-  });
-
-  router.post('/users', (req, res) {
-    final int id = req.body['id'];
-    final String email = req.body['email']?.trim();
-
-    if (id == null) {
-      res.status(400).json({
-        'errors': [
-          {'key': 'id', 'message': 'ID is required'}
-        ]
-      });
-      return;
-    }
-
-    if (users.firstWhere((u) => u.id == id, orElse: () => null) != null) {
-      res.status(400).json({
-        'errors': [
-          {'key': 'id', 'message': 'ID must be unique'}
-        ]
-      });
-      return;
-    }
-
-    if (email == null || email.isEmpty) {
-      res.status(400).json({
-        'errors': [
-          {'key': 'email', 'message': 'Email is required'}
-        ]
-      });
-      return;
-    }
-
-    final user = User(
-      id: req.body['id'],
-      email: req.body['email'],
-    );
-
-    users.add(user);
-
-    res.status(201).json({
-      'user': user.toJson(),
-    });
-  });
-
-  return router;
-}
diff --git a/example/body_parser.dart b/example/body_parser.dart
new file mode 100644
index 0000000..e0b2983
--- /dev/null
+++ b/example/body_parser.dart
@@ -0,0 +1,18 @@
+import 'package:dart_express/dart_express.dart';
+
+main() {
+  final app = express();
+
+  app.use(BodyParser.json());
+
+  app.post('/post', (req, res) {
+    res.send({
+      'body': req.body,
+    });
+  });
+
+  app.listen(
+    port: 3000,
+    cb: (port) => print('Listening on port $port'),
+  );
+}
diff --git a/example/dart_express_example.dart b/example/dart_express_example.dart
deleted file mode 100644
index c5d7d90..0000000
--- a/example/dart_express_example.dart
+++ /dev/null
@@ -1,26 +0,0 @@
-import 'package:dart_express/dart_express.dart';
-import 'package:path/path.dart' as path;
-import './api_routes.dart';
-import './view_routes.dart';
-
-const int port = 5000;
-
-void main() {
-  final app = express();
-
-  app.use(BodyParser.json());
-  app.use(CorsMiddleware.use());
-  app.use(LoggerMiddleware.use(includeImmediate: true));
-
-  app.engine(MarkdownEngine.use());
-  app.engine(MustacheEngine.use());
-
-  app.set('print routes', true);
-  app.set('views', path.join(path.current, 'example/views'));
-  app.set('view engine', 'mustache');
-
-  app.useRouter('/api/', apiRouter());
-  app.useRouter('/', viewRouter());
-
-  app.listen(port: port, cb: (int port) => print('Listening on port $port'));
-}
diff --git a/example/https_requests.dart b/example/https_requests.dart
new file mode 100644
index 0000000..0d0181f
--- /dev/null
+++ b/example/https_requests.dart
@@ -0,0 +1,32 @@
+import 'dart:io';
+
+import 'package:dart_express/dart_express.dart';
+
+main() {
+  final app = express();
+
+  app.get('/', (req, res) {
+    res.json({
+      'hello': 'world',
+      'test': true,
+    });
+  });
+
+  final chain = Platform.script.resolve('certificates/chain.pem').toFilePath();
+  final key = Platform.script.resolve('certificates/key.pem').toFilePath();
+  final context = SecurityContext()
+    ..useCertificateChain(chain)
+    ..usePrivateKey(key);
+
+  app.listen(
+    port: 80,
+    cb: (port) => print('listening for http on port $port'),
+  );
+
+  //listen for https requests
+  app.listenHttps(
+    context,
+    port: 443,
+    cb: (port) => print('Listening for https on port $port'),
+  );
+}
diff --git a/example/more_advanced_api.dart b/example/more_advanced_api.dart
new file mode 100644
index 0000000..277b17a
--- /dev/null
+++ b/example/more_advanced_api.dart
@@ -0,0 +1,211 @@
+import 'package:collection/collection.dart' show IterableExtension;
+import 'package:dart_express/dart_express.dart';
+
+const int port = 5000;
+
+class User {
+  final int id;
+  final String? email;
+
+  User({
+    required this.id,
+    required this.email,
+  });
+
+  User copyWith({String? email}) {
+    return User(id: id, email: email ?? this.email);
+  }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'id': id,
+      'email': email,
+    };
+  }
+}
+
+Router apiRouter() {
+  final router = Router();
+  final users = [
+    User(id: 1, email: 'test@example.com'),
+    User(id: 2, email: 'test2@example.com'),
+  ];
+
+  router.get('/users', (req, res) {
+    res.status(200).json({
+      'users': users.map((u) => u.toJson()).toList(),
+    });
+  });
+
+  router.post('/users', (req, res) {
+    final int? id = req.body['id'];
+    final String? email = req.body['email']?.trim();
+    final Map<String, List<String>> errors = {};
+
+    if (id == null) {
+      final errorMessage = 'ID is required';
+
+      if (errors.containsKey('id')) {
+        errors['id']!.add(errorMessage);
+      } else {
+        errors['id'] = [errorMessage];
+      }
+    }
+
+    if (users.firstWhereOrNull((u) => u.id == id) != null) {
+      final errorMessage = 'ID must be unique.';
+
+      if (errors.containsKey('id')) {
+        errors['id']!.add(errorMessage);
+      } else {
+        errors['id'] = [errorMessage];
+      }
+    }
+
+    if (email == null || email.isEmpty) {
+      final errorMessage = 'Email is required';
+
+      if (errors.containsKey('email')) {
+        errors['email']!.add(errorMessage);
+      } else {
+        errors['email'] = [errorMessage];
+      }
+    }
+
+    if (email != null && !email.contains('@')) {
+      final errorMessage = 'Email is not valid.';
+
+      if (errors.containsKey('email')) {
+        errors['email']!.add(errorMessage);
+      } else {
+        errors['email'] = [errorMessage];
+      }
+    }
+
+    if (errors.keys.isNotEmpty) {
+      final List<Map<String, String>> errorJson = [];
+
+      for (final key in errors.keys) {
+        for (final errorMessage in errors[key]!) {
+          errorJson.add({'key': key, 'message': errorMessage});
+        }
+      }
+
+      return res.json({
+        'errors': errorJson,
+      });
+    }
+
+    final user = User(id: id!, email: email!);
+
+    users.add(user);
+
+    res.status(201).json({
+      'user': user.toJson(),
+    });
+  });
+
+  router.get('/users/:userId', (req, res) {
+    final String userId = req.params['userId'];
+    final id = int.tryParse(userId);
+
+    if (id == null) {
+      return res.status(404).end();
+    }
+
+    final user = users.firstWhereOrNull((element) => element.id == id);
+
+    if (user == null) {
+      return res.status(404).end();
+    }
+
+    return res.json({
+      'user': user.toJson(),
+    });
+  });
+
+  router.post('/users/:userId', (req, res) {
+    final String userId = req.params['userId'];
+    final id = int.tryParse(userId);
+    final email = req.body['email'];
+    final Map<String, List<String>> errors = {};
+
+    if (email == null || email.isEmpty) {
+      final errorMessage = 'Email is required';
+
+      if (errors.containsKey('email')) {
+        errors['email']!.add(errorMessage);
+      } else {
+        errors['email'] = [errorMessage];
+      }
+    }
+
+    if (email != null && !email.contains('@')) {
+      final errorMessage = 'Email is not valid.';
+
+      if (errors.containsKey('email')) {
+        errors['email']!.add(errorMessage);
+      } else {
+        errors['email'] = [errorMessage];
+      }
+    }
+
+    if (errors.keys.isNotEmpty) {
+      final List<Map<String, String>> errorJson = [];
+
+      for (final key in errors.keys) {
+        for (final errorMessage in errors[key]!) {
+          errorJson.add({'key': key, 'message': errorMessage});
+        }
+      }
+
+      return res.json({
+        'errors': errorJson,
+      });
+    }
+
+    final user = users.firstWhereOrNull((element) => element.id == id);
+
+    if (user == null) {
+      return res.status(404).end();
+    }
+
+    final index = users.indexWhere((element) => element.id == id);
+    users[index] = user.copyWith(email: email);
+
+    return res.json({
+      'user': user.toJson(),
+    });
+  });
+
+  router.delete('/users/:userId', (req, res) {
+    final String userId = req.params['userId'];
+    final id = int.tryParse(userId);
+    final user = users.firstWhereOrNull((element) => element.id == id);
+
+    if (user == null) {
+      return res.status(404).end();
+    }
+
+    users.remove(user);
+
+    return res.status(200).end();
+  });
+
+  return router;
+}
+
+void main() {
+  final app = express();
+
+  app.use(BodyParser.json());
+  app.use(CorsMiddleware.use());
+  app.use(LoggerMiddleware.use(includeImmediate: true));
+
+  app.useRouter('/api/', apiRouter());
+
+  app.listen(
+    port: port,
+    cb: (int port) => print('Listening on port $port'),
+  );
+}
diff --git a/example/route_parameters.dart b/example/route_parameters.dart
new file mode 100644
index 0000000..4b6681c
--- /dev/null
+++ b/example/route_parameters.dart
@@ -0,0 +1,17 @@
+import 'package:dart_express/dart_express.dart';
+
+main() {
+  final app = express();
+
+  app.get('/users/:userId/posts/:postId', (req, res) {
+    res.json({
+      'userId': req.params['userId'],
+      'postId': req.params['postId'],
+    });
+  });
+
+  app.listen(
+    port: 3000,
+    cb: (port) => print('Listening on port $port'),
+  );
+}
diff --git a/example/simple.dart b/example/simple.dart
new file mode 100644
index 0000000..2c8cb7e
--- /dev/null
+++ b/example/simple.dart
@@ -0,0 +1,17 @@
+import 'package:dart_express/dart_express.dart';
+
+main() {
+  final app = express();
+
+  app.get('/', (req, res) {
+    res.json({
+      'hello': 'world',
+      'test': true,
+    });
+  });
+
+  app.listen(
+    port: 3000,
+    cb: (port) => print('Listening on port $port'),
+  );
+}
diff --git a/example/view_routes.dart b/example/view_routes.dart
deleted file mode 100644
index 0aa73c3..0000000
--- a/example/view_routes.dart
+++ /dev/null
@@ -1,24 +0,0 @@
-import 'package:dart_express/dart_express.dart';
-
-Router viewRouter() {
-  final router = Router();
-
-  router.get('/example', (req, res) {
-    res.render('example.md');
-  });
-
-  router.all('/secret', (req, res) {
-    print('Accessing the secret section');
-    req.next();
-  });
-
-  router.get('/secret', (req, res) {
-    res.send('Secret Home Page');
-  });
-
-  router.get('/secret/2', (req, res) {
-    res.send('Secret Home Page');
-  });
-
-  return router;
-}
diff --git a/example/views/about.mustache b/example/views/about.mustache
deleted file mode 100644
index 3bb2c57..0000000
--- a/example/views/about.mustache
+++ /dev/null
@@ -1,16 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <meta http-equiv="X-UA-Compatible" content="ie=edge">
-    <title>About</title>
-</head>
-<body>
-    <h1>About Page</h1>
-
-    {{#person}}
-        <h4>{{ first_name }}</h4>
-    {{/person}}
-</body>
-</html>
\ No newline at end of file
diff --git a/example/views/example.md b/example/views/example.md
deleted file mode 100644
index 3a26b76..0000000
--- a/example/views/example.md
+++ /dev/null
@@ -1,9 +0,0 @@
-# About Dart Express
-Dart Express is a library built in the dart programming language for building quick and easy web servers.
-
-## TO DO List
-
-- Check it out
-- On Github
-- Or pub.dev
-- to get started
diff --git a/example/views/index.mustache b/example/views/index.mustache
deleted file mode 100644
index 27a323e..0000000
--- a/example/views/index.mustache
+++ /dev/null
@@ -1,13 +0,0 @@
-<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <meta http-equiv="X-UA-Compatible" content="ie=edge">
-    <title>My Index Page</title>
-</head>
-<body>
-    <h1>Index Page</h1>
-    <p>Does this work?</p>
-</body>
-</html>
\ No newline at end of file
diff --git a/lib/dart_express.dart b/lib/dart_express.dart
index 70b7819..d6e2cc9 100644
--- a/lib/dart_express.dart
+++ b/lib/dart_express.dart
@@ -9,7 +9,6 @@ import 'dart:convert' as convert;
 import 'dart:async';
 import 'dart:io';
 import 'package:markdown/markdown.dart' deferred as markdown;
-import 'package:mustache4dart/mustache4dart.dart' deferred as mustache;
 import 'package:path_to_regexp/path_to_regexp.dart';
 
 export 'dart:io' show HttpStatus;
@@ -39,6 +38,5 @@ part 'src/exceptions/view_exception.dart';
 
 /// View Engines
 part 'src/engines/engine.dart';
-part 'src/engines/mustache.dart';
 part 'src/engines/html.dart';
 part 'src/engines/markdown.dart';
diff --git a/lib/src/app.dart b/lib/src/app.dart
index ea92cc6..745e2da 100644
--- a/lib/src/app.dart
+++ b/lib/src/app.dart
@@ -8,18 +8,18 @@ class _AppSettings {
 
   _AppSettings({
     this.cache = true,
-    String viewsPath,
+    String? viewsPath,
     this.printRoutes = false,
     this.viewEngine = 'html',
   }) : viewsPath = viewsPath ?? path.absolute('views');
 }
 
 class App {
-  _AppSettings _settings;
-  Map<String, dynamic> cache;
-  Map<String, Engine> _engines;
-  HttpServer _server;
-  Router _router;
+  late _AppSettings _settings;
+  late Map<String, _View> cache;
+  late Map<String, Engine> _engines;
+  late HttpServer _server;
+  Router? _router;
 
   App() {
     _settings = _AppSettings();
@@ -71,7 +71,7 @@ class App {
   App use(Function cb) {
     _lazyRouter();
 
-    _router.use(cb);
+    _router!.use(cb as dynamic Function(Request, Response));
 
     return this;
   }
@@ -91,18 +91,18 @@ class App {
   /// Examples:
   ///
   /// app.engine(JaelEngine.use());
-  ///
   /// app.engine(MustacheEngine.use());
-  ///
   /// app.engine(MarkdownEngine.use());
   App engine(Engine engine) {
-    if (engine.ext == null) {
-      throw Error.safeToString('Engine extension must be defined.');
+    if (engine.ext.isEmpty) {
+      throw Error.safeToString('View Engine extension must be defined.');
     }
 
-    if (_engines[engine.ext] != null) {
+    if (_engines.containsKey(engine.ext)) {
+      final existingEngine = _engines[engine.ext];
+
       throw Error.safeToString(
-        'A View engine for the ${engine.ext} extension has already been defined.',
+        'A view engine has already been defined for extension ${engine.ext}: $existingEngine',
       );
     }
 
@@ -112,8 +112,8 @@ class App {
   }
 
   /// Handles DELETE requests to the specified path
-  _Route delete(String path, Function cb) =>
-      _buildRoute(path, _HTTPMethods.delete, cb);
+  _Route delete(String path, Function cb) => _buildRoute(
+      path, _HTTPMethods.delete, cb as dynamic Function(Request, Response));
 
   /// Handles GET requests to the specified path
   _Route get(String path, RouteMethod cb) =>
@@ -149,8 +149,11 @@ class App {
   /// Starts the HTTP server listening on the specified port
   ///
   /// All Request and Response objects will be wrapped and handled by the Router
-  Future<void> listen(
-      {InternetAddress address, int port, Function(int) cb}) async {
+  Future<void> listen({
+    InternetAddress? address,
+    required int port,
+    Function(int)? cb,
+  }) async {
     _server = await HttpServer.bind(
       address ?? InternetAddress.loopbackIPv4,
       port,
@@ -166,9 +169,9 @@ class App {
   /// You can add Certifications to the [SecurityContext]
   Future<void> listenHttps(
     SecurityContext securityContext, {
-    InternetAddress address,
-    int port,
-    Function(int) cb,
+    InternetAddress? address,
+    required int port,
+    Function(int)? cb,
   }) async {
     _server = await HttpServer.bindSecure(
         address ?? InternetAddress.loopbackIPv4, port, securityContext);
@@ -176,12 +179,12 @@ class App {
     _mapToRoutes(cb);
   }
 
-  void _mapToRoutes(Function(int) cb) {
+  void _mapToRoutes(Function(int)? cb) {
     _server.listen((HttpRequest req) {
       final request = Request(req);
       final response = Response(req.response, this);
 
-      _router.handle(request, response);
+      _router!.handle(request, response);
     });
 
     if (_settings.printRoutes) {
@@ -200,18 +203,15 @@ class App {
   /// Provide a Map of local variables to the template
   void render(
     String fileName,
-    Map<String, dynamic> locals,
+    Map<String, dynamic>? locals,
     Function callback,
   ) {
-    _settings.cache ??= true;
-
     final view = _getViewFromFileName(fileName);
-
     view.render(locals, callback);
   }
 
   void _printRoutes() {
-    _router.stack.where((layer) => layer.route != null).forEach((layer) {
+    _router!.stack.where((layer) => layer.route != null).forEach((layer) {
       print('[${layer.method}] ${layer.path}');
     });
   }
@@ -222,36 +222,19 @@ class App {
   Router _lazyRouter() => _router ??= Router().use(_InitMiddleware.init);
 
   _View _getViewFromFileName(String fileName) {
-    _View view;
-
-    if (_settings.cache) {
-      view = cache[fileName];
+    if (_settings.cache && cache.containsKey(fileName)) {
+      return cache[fileName]!;
     }
 
-    if (view == null) {
-      view = _View(
-        fileName,
-        defaultEngine: _settings.viewEngine,
-        engines: _engines,
-        rootPath: _settings.viewsPath,
-      );
-
-      if (view.filePath == null) {
-        String dirs;
-
-        if (view.rootPath is List) {
-          dirs =
-              'directories "${view.rootPath.join(', ')}" or "${view.rootPath[view.rootPath.length - 1]}"';
-        } else {
-          dirs = 'directory "${view.rootPath}"';
-        }
-
-        throw _ViewException(view, dirs);
-      }
+    final view = _View(
+      fileName,
+      defaultEngine: _settings.viewEngine,
+      engines: _engines,
+      rootPath: _settings.viewsPath,
+    );
 
-      if (_settings.cache) {
-        cache[fileName] = view;
-      }
+    if (_settings.cache) {
+      cache[fileName] = view;
     }
 
     return view;
diff --git a/lib/src/engines/engine.dart b/lib/src/engines/engine.dart
index 2ea373e..05d716e 100644
--- a/lib/src/engines/engine.dart
+++ b/lib/src/engines/engine.dart
@@ -1,8 +1,8 @@
 part of dart_express;
 
-typedef HandlerCallback = Function(dynamic e, String rendered);
+typedef HandlerCallback = Function(dynamic e, String? rendered);
 typedef Handler = Function(
-    String filePath, Map<String, dynamic> locals, HandlerCallback cb);
+    String filePath, Map<String, dynamic>? locals, HandlerCallback cb);
 
 class Engine {
   final String ext;
diff --git a/lib/src/engines/html.dart b/lib/src/engines/html.dart
index 1be0fc3..02103f4 100644
--- a/lib/src/engines/html.dart
+++ b/lib/src/engines/html.dart
@@ -6,9 +6,9 @@ class HtmlEngine {
   /// Called when rendering an HTML file in the Response
   ///
   /// [locals] is ignored for HTML files
-  static Future<String> handler(
+  static Future<String?> handler(
     String filePath,
-    Map<String, dynamic> locals,
+    Map<String, dynamic>? locals,
     HandlerCallback callback, [
     FileRepository fileRepository = const _RealFileRepository(),
   ]) async {
diff --git a/lib/src/engines/markdown.dart b/lib/src/engines/markdown.dart
index b28dbd3..3cea2ad 100644
--- a/lib/src/engines/markdown.dart
+++ b/lib/src/engines/markdown.dart
@@ -14,9 +14,9 @@ class MarkdownEngine {
   /// locals['beforeMarkdown'] will be rendered at the top of the body before the markdown.
   ///
   /// locals['afterMarkdown'] will be rendered at the bottom of the body after the markdown
-  static Future<String> handler(
+  static Future<String?> handler(
     String filePath,
-    Map<String, dynamic> locals,
+    Map<String, dynamic>? locals,
     HandlerCallback callback, [
     FileRepository fileRepository = const _RealFileRepository(),
   ]) async {
@@ -25,8 +25,12 @@ class MarkdownEngine {
     try {
       final fileContents =
           await fileRepository.readAsString(Uri.file(filePath));
-      final rendered =
-          _wrapInHTMLTags(markdown.markdownToHtml(fileContents), locals);
+
+      final rendered = _wrapInHTMLTags(
+        markdown.markdownToHtml(fileContents),
+        locals ?? {},
+      );
+
       callback(null, rendered);
       return rendered;
     } catch (e) {
@@ -35,7 +39,10 @@ class MarkdownEngine {
     }
   }
 
-  static String _wrapInHTMLTags(String html, Map<String, dynamic> options) {
+  static String _wrapInHTMLTags(
+    String html,
+    Map<String, dynamic> options,
+  ) {
     return '''
     <html>
     <head>
diff --git a/lib/src/engines/mustache.dart b/lib/src/engines/mustache.dart
deleted file mode 100644
index ff76868..0000000
--- a/lib/src/engines/mustache.dart
+++ /dev/null
@@ -1,27 +0,0 @@
-part of dart_express;
-
-class MustacheEngine {
-  static String ext = '.mustache';
-
-  static Future<void> handler(
-    String filePath,
-    Map<String, dynamic> options,
-    HandlerCallback callback, [
-    FileRepository fileRepository = const _RealFileRepository(),
-  ]) async {
-    await mustache.loadLibrary();
-
-    try {
-      final fileContents =
-          await fileRepository.readAsString(Uri.file(filePath));
-      final rendered = mustache.render(fileContents, options ?? {});
-
-      return callback(null, rendered);
-    } catch (e) {
-      callback(e, null);
-      return;
-    }
-  }
-
-  static Engine use() => Engine(MustacheEngine.ext, MustacheEngine.handler);
-}
diff --git a/lib/src/exceptions/view_exception.dart b/lib/src/exceptions/view_exception.dart
index 731dac6..80333ec 100644
--- a/lib/src/exceptions/view_exception.dart
+++ b/lib/src/exceptions/view_exception.dart
@@ -1,13 +1,13 @@
 part of dart_express;
 
 class _ViewException implements Error {
-  final _View view;
+  final String name;
+  final String ext;
   final String directory;
 
-  _ViewException(this.view, this.directory);
+  _ViewException(this.name, this.ext, this.directory);
 
-  String get message =>
-      'ViewException(Failed to find ${view.name}${view.ext} in $directory)';
+  String get message => 'ViewException(Failed to find $name$ext in $directory)';
 
   @override
   String toString() => message;
diff --git a/lib/src/layer.dart b/lib/src/layer.dart
index 7bcd512..c1d749f 100644
--- a/lib/src/layer.dart
+++ b/lib/src/layer.dart
@@ -1,31 +1,33 @@
 part of dart_express;
 
 class _Layer {
-  final String _path;
-  String method;
+  final String? _path;
+  String? method;
   RouteMethod handle;
-  _Route route;
-  String name;
-  RegExp regExp;
-  List<String> parameters;
-  Map<String, String> routeParams;
+  _Route? route;
+  String? name;
+  List<String>? parameters;
+  late Map<String, String> routeParams;
 
-  String get path => _path ?? route.path;
+  String get path => _path ?? route?.path ?? '';
+  RegExp get regExp => pathToRegExp(path, parameters: parameters);
 
-  _Layer(this._path, {this.method, this.handle, this.route, this.name}) {
-    name = name ?? '<anonymous>';
-    parameters = [];
-    regExp = pathToRegExp(path, parameters: parameters);
-    routeParams = {};
-  }
+  _Layer(
+    this._path, {
+    required this.handle,
+    this.route,
+    this.method,
+    this.name = '<anonymous>',
+  })  : parameters = [],
+        routeParams = {};
 
   bool match(String pathToCheck, String methodToCheck) {
     if (_pathMatches(pathToCheck) &&
         method != null &&
-        method.toUpperCase() == methodToCheck.toUpperCase()) {
-      if (parameters.isNotEmpty) {
-        final match = regExp.matchAsPrefix(pathToCheck);
-        routeParams.addAll(extract(parameters, match));
+        method!.toUpperCase() == methodToCheck.toUpperCase()) {
+      if (parameters!.isNotEmpty) {
+        final match = regExp.matchAsPrefix(pathToCheck)!;
+        routeParams.addAll(extract(parameters!, match));
       }
 
       return true;
@@ -64,7 +66,7 @@ class _Layer {
   }
 
   bool _pathMatches(String pathToCheck) {
-    if (route == null || path == null) {
+    if (route == null || path.isEmpty) {
       return false;
     }
 
diff --git a/lib/src/middleware/body_parser.dart b/lib/src/middleware/body_parser.dart
index 08940c4..7b7d8d9 100644
--- a/lib/src/middleware/body_parser.dart
+++ b/lib/src/middleware/body_parser.dart
@@ -8,7 +8,7 @@ class BodyParser {
       if (req.method == 'POST' &&
           contentType != null &&
           contentType.mimeType == 'application/json') {
-        convertBodyToJson(req).then((Map<String, dynamic> json) {
+        convertBodyToJson(req).then((Map<String, dynamic>? json) {
           if (json != null) {
             req.body = json;
           }
@@ -21,11 +21,13 @@ class BodyParser {
     };
   }
 
-  static Future<Map<String, dynamic>> convertBodyToJson(Request request) async {
+  static Future<Map<String, dynamic>?> convertBodyToJson(
+    Request request,
+  ) async {
     try {
       final content = await convert.utf8.decoder.bind(request.request).join();
 
-      return convert.jsonDecode(content) as Map<String, dynamic>;
+      return convert.jsonDecode(content) as Map<String, dynamic>?;
     } catch (e) {
       print(e);
 
diff --git a/lib/src/middleware/cors.dart b/lib/src/middleware/cors.dart
index b3aabb4..83a96d6 100644
--- a/lib/src/middleware/cors.dart
+++ b/lib/src/middleware/cors.dart
@@ -8,7 +8,7 @@ class CorsOptions {
   final bool credentials;
   final List<String> allowedHeaders;
   final List<String> exposedHeaders;
-  final int maxAge;
+  final int? maxAge;
 
   const CorsOptions({
     this.origin = '*',
@@ -30,13 +30,13 @@ class CorsOptions {
 
   CorsOptions copyWith({
     dynamic origin,
-    List<String> methods,
-    bool preflightContinue,
-    int optionsSuccessStatus,
-    bool credentials,
-    List<String> allowedHeaders,
-    List<String> exposedHeaders,
-    int maxAge,
+    List<String>? methods,
+    bool? preflightContinue,
+    int? optionsSuccessStatus,
+    bool? credentials,
+    List<String>? allowedHeaders,
+    List<String>? exposedHeaders,
+    int? maxAge,
   }) {
     return CorsOptions(
       origin: origin ?? this.origin,
@@ -67,7 +67,7 @@ class CorsMiddleware {
     bool credentials = false,
     List<String> allowedHeaders = const <String>[],
     List<String> exposedHeaders = const <String>[],
-    int maxAge,
+    int? maxAge,
   }) {
     final options = CorsOptions(
       origin: origin,
@@ -81,7 +81,7 @@ class CorsMiddleware {
     );
 
     return (Request req, Response res) {
-      final headers = <MapEntry>[];
+      final headers = <MapEntry?>[];
 
       if (req.method == _HTTPMethods.options) {
         headers.addAll(configureOrigin(options, req));
@@ -110,13 +110,13 @@ class CorsMiddleware {
     };
   }
 
-  static void _applyHeaders(Response res, List<MapEntry> headers) {
+  static void _applyHeaders(Response res, List<MapEntry?> headers) {
     headers
         .where((mapEntry) => mapEntry != null)
-        .forEach((mapEntry) => res.headers.add(mapEntry.key, mapEntry.value));
+        .forEach((mapEntry) => res.headers.add(mapEntry!.key, mapEntry.value));
   }
 
-  static bool isOriginAllowed(String origin, dynamic allowedOrigin) {
+  static bool isOriginAllowed(String? origin, dynamic allowedOrigin) {
     if (allowedOrigin is List) {
       for (var i = 0; i < allowedOrigin.length; ++i) {
         if (isOriginAllowed(origin, allowedOrigin[i])) {
@@ -127,7 +127,7 @@ class CorsMiddleware {
     } else if (allowedOrigin is String) {
       return origin == allowedOrigin;
     } else if (allowedOrigin is RegExp) {
-      return allowedOrigin.hasMatch(origin);
+      return allowedOrigin.hasMatch(origin!);
     } else {
       return allowedOrigin != null;
     }
@@ -173,7 +173,7 @@ class CorsMiddleware {
     );
   }
 
-  static MapEntry configureCredentials(CorsOptions options) {
+  static MapEntry? configureCredentials(CorsOptions options) {
     if (options.credentials) {
       return MapEntry('Access-Control-Allow-Credentials', 'true');
     }
@@ -183,27 +183,24 @@ class CorsMiddleware {
 
   static List<MapEntry> configureAllowedHeaders(
       CorsOptions options, Request req) {
-    String allowedHeaders;
+    String? allowedHeaders;
     final headers = <MapEntry>[];
 
-    if (options.allowedHeaders == null) {
-      allowedHeaders = req.headers.value('access-control-request-headers');
-
-      headers.add(
-        MapEntry('Vary', 'Access-Control-Request-Headers'),
-      );
+    if (options.allowedHeaders.isEmpty) {
+      allowedHeaders = req.headers.value('access-control-request-headers')!;
+      headers.add(MapEntry('Vary', 'Access-Control-Request-Headers'));
     } else {
       allowedHeaders = options.allowedHeaders.join(',');
     }
 
-    if (allowedHeaders != null && allowedHeaders.isNotEmpty) {
+    if (allowedHeaders.isNotEmpty) {
       headers.add(MapEntry('Access-Control-Allow-Headers', allowedHeaders));
     }
 
     return headers;
   }
 
-  static MapEntry configureMaxAge(CorsOptions options) {
+  static MapEntry? configureMaxAge(CorsOptions options) {
     if (options.maxAge != null) {
       return MapEntry(
         'Access-Control-Max-Age',
@@ -214,17 +211,12 @@ class CorsMiddleware {
     return null;
   }
 
-  static MapEntry configureExposedHeaders(CorsOptions options) {
-    String headers;
-
-    if (headers == null) {
-      return null;
-    } else if (headers is List) {
-      headers = options.exposedHeaders.join(',');
-    }
-
-    if (headers != null && headers.isNotEmpty) {
-      return MapEntry('Access-Control-Expose-Headers', headers);
+  static MapEntry? configureExposedHeaders(CorsOptions options) {
+    if (options.exposedHeaders.isNotEmpty) {
+      return MapEntry(
+        'Access-Control-Expose-Headers',
+        options.exposedHeaders.join(','),
+      );
     }
 
     return null;
diff --git a/lib/src/middleware/init.dart b/lib/src/middleware/init.dart
index 08333be..3e8642d 100644
--- a/lib/src/middleware/init.dart
+++ b/lib/src/middleware/init.dart
@@ -4,6 +4,6 @@ class _InitMiddleware {
   static final String name = 'EXPRESS_INIT';
 
   static void init(Request req, Response res) {
-    req?.next();
+    req.next();
   }
 }
diff --git a/lib/src/middleware/logger.dart b/lib/src/middleware/logger.dart
index 0bc320c..db76189 100644
--- a/lib/src/middleware/logger.dart
+++ b/lib/src/middleware/logger.dart
@@ -33,5 +33,5 @@ class LoggerMiddleware {
   }
 
   static String _getIpAddress(Request req) =>
-      req.connectionInfo.remoteAddress.address.toString();
+      req.connectionInfo!.remoteAddress.address.toString();
 }
diff --git a/lib/src/repositories/file_repository.dart b/lib/src/repositories/file_repository.dart
index 547902a..6781947 100644
--- a/lib/src/repositories/file_repository.dart
+++ b/lib/src/repositories/file_repository.dart
@@ -6,7 +6,7 @@ abstract class FileRepository {
   Future<String> readAsString(Uri uri);
 }
 
-class _RealFileRepository extends FileRepository {
+class _RealFileRepository implements FileRepository {
   const _RealFileRepository();
 
   @override
diff --git a/lib/src/request.dart b/lib/src/request.dart
index 692f1a8..ec0cd47 100644
--- a/lib/src/request.dart
+++ b/lib/src/request.dart
@@ -2,23 +2,21 @@ part of dart_express;
 
 class Request {
   final HttpRequest _request;
-  Next next;
-  Map<String, dynamic> body;
-  Map<String, dynamic> params;
+  late Next next;
+  late Map<String, dynamic> body;
+  late Map<String, dynamic> params;
 
   Request(this._request) {
     body = <String, dynamic>{};
-
-    if (request != null) {
-      params = Map.from(request.requestedUri.queryParameters);
-    }
+    params = Map.from(request.requestedUri.queryParameters);
+    next = () {};
   }
 
   HttpRequest get request => _request;
 
-  X509Certificate get certificate => request.certificate;
+  X509Certificate? get certificate => request.certificate;
 
-  HttpConnectionInfo get connectionInfo => request.connectionInfo;
+  HttpConnectionInfo? get connectionInfo => request.connectionInfo;
 
   int get contentLength => request.contentLength;
 
diff --git a/lib/src/response.dart b/lib/src/response.dart
index 55e01d0..b86d42b 100644
--- a/lib/src/response.dart
+++ b/lib/src/response.dart
@@ -8,7 +8,7 @@ class Response {
 
   Response send(dynamic body) {
     if (body is Map) {
-      json(body);
+      json(body as Map<String, dynamic>);
     } else if (body is String) {
       if (headers.contentType == null) {
         headers.add('Content-Type', 'text/plain');
@@ -22,7 +22,7 @@ class Response {
     return this;
   }
 
-  void render(String viewName, [Map<String, dynamic> locals]) {
+  void render(String viewName, [Map<String, dynamic>? locals]) {
     app.render(viewName, locals, (err, data) {
       if (err != null) {
         print(err);
@@ -56,14 +56,14 @@ class Response {
     return this;
   }
 
-  convert.Encoding encoding;
+  convert.Encoding? encoding;
 
   int get statusCode => response.statusCode;
   set statusCode(int newCode) => response.statusCode = newCode;
 
   Future close() => response.close();
 
-  HttpConnectionInfo get connectionInfo => response.connectionInfo;
+  HttpConnectionInfo? get connectionInfo => response.connectionInfo;
 
   List<Cookie> get cookies => response.cookies;
 
@@ -78,7 +78,7 @@ class Response {
     String location, {
     int status = HttpStatus.movedTemporarily,
   }) =>
-      response.redirect(Uri.tryParse(location), status: status);
+      response.redirect(Uri.tryParse(location)!, status: status);
 
   void write(Object obj) => response.write(obj);
   void location(String path) => headers.add('Location', path);
diff --git a/lib/src/router.dart b/lib/src/router.dart
index 740c8d9..6e3090b 100644
--- a/lib/src/router.dart
+++ b/lib/src/router.dart
@@ -26,7 +26,7 @@ class Router {
       _Layer(
         path,
         method: method,
-        handle: handle ?? (req, res) {},
+        handle: handle,
         route: route,
       ),
     );
@@ -35,8 +35,8 @@ class Router {
   }
 
   /// Handles DELETE requests to the specified path
-  _Route delete(String path, Function cb) =>
-      route(path, _HTTPMethods.delete, cb);
+  _Route delete(String path, Function cb) => route(
+      path, _HTTPMethods.delete, cb as dynamic Function(Request, Response));
 
   /// Handles GET requests to the specified path
   _Route get(String path, RouteMethod cb) => route(path, _HTTPMethods.get, cb);
@@ -80,18 +80,18 @@ class Router {
   }
 
   void handle(Request req, Response res) {
-    var self = this;
-    var stack = self.stack;
-    var index = 0;
+    Router self = this;
+    final stack = self.stack;
+    int index = 0;
 
     req.next = () {
       final path = req.requestedUri.path;
       final method = req.method;
 
       // find next matching layer
-      _Layer layer;
+      late _Layer layer;
       var match = false;
-      _Route route;
+      _Route? route;
 
       while (match != true && index < stack.length) {
         layer = stack[index++];
@@ -106,10 +106,8 @@ class Router {
 
         if (route.stack.isNotEmpty) {
           route.stack.first.handleRequest(req, res);
-        } else if (layer.handle != null) {
-          layer.handleRequest(req, res);
         } else {
-          res.status(HttpStatus.notFound).close();
+          layer.handleRequest(req, res);
         }
       }
 
diff --git a/lib/src/view.dart b/lib/src/view.dart
index df74726..af4d992 100644
--- a/lib/src/view.dart
+++ b/lib/src/view.dart
@@ -2,29 +2,28 @@ part of dart_express;
 
 class _View {
   dynamic rootPath;
-  String defaultEngine;
-  String filePath;
-  String ext;
+  String? defaultEngine;
+  late String ext;
   String name;
-  Engine engine;
+  late String filePath;
+  late Engine engine;
 
   _View(
     this.name, {
     this.rootPath = '/',
     this.defaultEngine,
-    Map<String, Engine> engines,
+    required Map<String, Engine> engines,
   }) {
-    ext = path.extension(name);
+    final extension = path.extension(name);
 
-    if (ext == null && defaultEngine == null) {
+    if (extension.isEmpty && defaultEngine == null) {
       throw Error.safeToString('No default engine or extension are provided.');
     }
 
     var fileName = name;
 
-    if (ext == null || ext.isEmpty) {
-      ext = defaultEngine[0] == '.' ? defaultEngine : '.$defaultEngine';
-
+    if (extension.isEmpty) {
+      ext = defaultEngine![0] == '.' ? defaultEngine! : '.$defaultEngine';
       fileName += ext;
     }
 
@@ -32,11 +31,18 @@ class _View {
     filePath = lookup(fileName);
   }
 
-  void render(Map<String, dynamic> options, Function callback) =>
-      engine.handler(filePath, options, callback);
+  void render(
+    Map<String, dynamic>? options,
+    Function callback,
+  ) =>
+      engine.handler(
+        filePath,
+        options,
+        callback as dynamic Function(dynamic, String?),
+      );
 
   String lookup(String fileName) {
-    String finalPath;
+    String? finalPath;
     final List<String> roots = rootPath is List ? rootPath : [rootPath];
 
     for (var i = 0; i < roots.length && finalPath == null; i++) {
@@ -50,18 +56,30 @@ class _View {
       finalPath = resolve(loc);
     }
 
+    if (finalPath == null) {
+      String dirs;
+
+      if (rootPath is List) {
+        dirs = 'directories "${rootPath.join(', ')}" or "${rootPath.last}"';
+      } else {
+        dirs = 'directory "$rootPath"';
+      }
+
+      throw _ViewException(name, ext, dirs);
+    }
+
     return finalPath;
   }
 
-  String resolve(filePath) {
-    if (_exists(filePath) && _isFile(filePath)) {
+  String? resolve(filePath) {
+    if (_exists(filePath) && _isFile(filePath)!) {
       return filePath;
     } else {
       return null;
     }
   }
 
-  bool _isFile(filePath) {
+  bool? _isFile(filePath) {
     try {
       return File.fromUri(Uri.file(filePath)).statSync().type ==
           FileSystemEntityType.file;
diff --git a/pubspec.yaml b/pubspec.yaml
index 8b3fbda..6c3168e 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -4,18 +4,19 @@ version: 0.5.3
 homepage: https://github.com/deriegle/dart-express
 
 environment:
-  sdk: ">=2.3.0 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   path: ^1.6.4
   file: ^6.0.0
   http: ^0.13.4
   meta: ^1.7.0
-  path_to_regexp: ^0.2.1
-  mustache4dart: ^3.0.0-dev.0.0
+  path_to_regexp: ^0.4.0
   markdown: ^4.0.1
+  collection: ^1.15.0-nullsafety.4
 
 dev_dependencies:
   mockito: ^5.0.17
   test: ^1.20.1
   lints: ^1.0.1
+  build_runner: ^2.1.7
diff --git a/test/dart_express_test.dart b/test/dart_express_test.dart
deleted file mode 100644
index 00dcd9e..0000000
--- a/test/dart_express_test.dart
+++ /dev/null
@@ -1,5 +0,0 @@
-// import 'package:dart_express/dart_express.dart';
-// import 'package:test/test.dart';
-
-void main() {
-}
diff --git a/test/engines/html_test.dart b/test/engines/html_test.dart
index 4756099..fb3af0c 100644
--- a/test/engines/html_test.dart
+++ b/test/engines/html_test.dart
@@ -1,10 +1,11 @@
 import 'dart:io';
 
 import 'package:dart_express/dart_express.dart';
+import 'package:mockito/annotations.dart';
 import 'package:test/test.dart';
 import 'package:mockito/mockito.dart';
 
-class MockFileRepository extends Mock implements FileRepository {}
+import 'html_test.mocks.dart';
 
 final mockHtml = '''
 <html>
@@ -17,6 +18,7 @@ final mockHtml = '''
 </html>
 ''';
 
+@GenerateMocks([FileRepository])
 void main() {
   test('HtmlEngine has the correct extension', () {
     expect(HtmlEngine.ext, '.html');
@@ -25,9 +27,9 @@ void main() {
   test('HtmlEngine handles reading a file correctly', () async {
     final filePath = './views/index.html';
     dynamic error;
-    String rendered;
+    String? rendered;
 
-    dynamic callback(dynamic err, String string) {
+    dynamic callback(dynamic err, String? string) {
       error = err;
       rendered = string;
     }
@@ -46,9 +48,9 @@ void main() {
   test('HtmlEngine handles exceptions correctly', () async {
     final filePath = './views/index.html';
     dynamic error;
-    String rendered;
+    String? rendered;
 
-    dynamic callback(dynamic err, String string) {
+    dynamic callback(dynamic err, String? string) {
       error = err;
       rendered = string;
     }
diff --git a/test/engines/html_test.mocks.dart b/test/engines/html_test.mocks.dart
new file mode 100644
index 0000000..675a1d8
--- /dev/null
+++ b/test/engines/html_test.mocks.dart
@@ -0,0 +1,31 @@
+// Mocks generated by Mockito 5.0.17 from annotations
+// in dart_express/test/engines/html_test.dart.
+// Do not manually edit this file.
+
+import 'dart:async' as _i3;
+
+import 'package:dart_express/dart_express.dart' as _i2;
+import 'package:mockito/mockito.dart' as _i1;
+
+// ignore_for_file: avoid_redundant_argument_values
+// ignore_for_file: avoid_setters_without_getters
+// ignore_for_file: comment_references
+// ignore_for_file: implementation_imports
+// ignore_for_file: invalid_use_of_visible_for_testing_member
+// ignore_for_file: prefer_const_constructors
+// ignore_for_file: unnecessary_parenthesis
+// ignore_for_file: camel_case_types
+
+/// A class which mocks [FileRepository].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockFileRepository extends _i1.Mock implements _i2.FileRepository {
+  MockFileRepository() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i3.Future<String> readAsString(Uri? uri) =>
+      (super.noSuchMethod(Invocation.method(#readAsString, [uri]),
+          returnValue: Future<String>.value('')) as _i3.Future<String>);
+}
diff --git a/test/engines/markdown_test.dart b/test/engines/markdown_test.dart
index 7e869fc..4e8c530 100644
--- a/test/engines/markdown_test.dart
+++ b/test/engines/markdown_test.dart
@@ -1,15 +1,17 @@
 import 'dart:io';
 
 import 'package:dart_express/dart_express.dart';
+import 'package:mockito/annotations.dart';
 import 'package:test/test.dart';
 import 'package:mockito/mockito.dart';
 
-class MockFileRepository extends Mock implements FileRepository {}
+import 'markdown_test.mocks.dart';
 
 final mockMarkdown = '''
 # Hello, world
 ''';
 
+@GenerateMocks([FileRepository])
 void main() {
   test('HtmlEngine has the correct extension', () {
     expect(MarkdownEngine.ext, '.md');
@@ -18,9 +20,9 @@ void main() {
   test('MarkdownEngine handles reading a file correctly', () async {
     final filePath = './views/index.md';
     dynamic error;
-    String rendered;
+    String? rendered;
 
-    dynamic callback(dynamic err, String string) {
+    dynamic callback(dynamic err, String? string) {
       error = err;
       rendered = string;
     }
@@ -40,9 +42,9 @@ void main() {
   test('MarkdownEngine handles exceptions correctly', () async {
     final filePath = './views/index.md';
     dynamic error;
-    String rendered;
+    String? rendered;
 
-    dynamic callback(dynamic err, String string) {
+    dynamic callback(dynamic err, String? string) {
       error = err;
       rendered = string;
     }
diff --git a/test/engines/markdown_test.mocks.dart b/test/engines/markdown_test.mocks.dart
new file mode 100644
index 0000000..20da311
--- /dev/null
+++ b/test/engines/markdown_test.mocks.dart
@@ -0,0 +1,31 @@
+// Mocks generated by Mockito 5.0.17 from annotations
+// in dart_express/test/engines/markdown_test.dart.
+// Do not manually edit this file.
+
+import 'dart:async' as _i3;
+
+import 'package:dart_express/dart_express.dart' as _i2;
+import 'package:mockito/mockito.dart' as _i1;
+
+// ignore_for_file: avoid_redundant_argument_values
+// ignore_for_file: avoid_setters_without_getters
+// ignore_for_file: comment_references
+// ignore_for_file: implementation_imports
+// ignore_for_file: invalid_use_of_visible_for_testing_member
+// ignore_for_file: prefer_const_constructors
+// ignore_for_file: unnecessary_parenthesis
+// ignore_for_file: camel_case_types
+
+/// A class which mocks [FileRepository].
+///
+/// See the documentation for Mockito's code generation for more information.
+class MockFileRepository extends _i1.Mock implements _i2.FileRepository {
+  MockFileRepository() {
+    _i1.throwOnMissingStub(this);
+  }
+
+  @override
+  _i3.Future<String> readAsString(Uri? uri) =>
+      (super.noSuchMethod(Invocation.method(#readAsString, [uri]),
+          returnValue: Future<String>.value('')) as _i3.Future<String>);
+}
diff --git a/test/engines/mustache_test.dart b/test/engines/mustache_test.dart
deleted file mode 100644
index a96b823..0000000
--- a/test/engines/mustache_test.dart
+++ /dev/null
@@ -1,97 +0,0 @@
-import 'dart:io';
-
-import 'package:dart_express/dart_express.dart';
-import 'package:test/test.dart';
-import 'package:mockito/mockito.dart';
-
-class MockFileRepository extends Mock implements FileRepository {}
-
-final mockMustache = '''
-<html>
-<head>
-  <title>Mock HTML Title</title>
-</head>
-<body>
-  {{#first_name}}
-    <h1>Hello, {{first_name}}</h1>
-  {{/first_name}}
-  {{^first_name}}
-    <h1>Hello, World</h1>
-  {{/first_name}}
-</body>
-</html>
-''';
-
-void main() {
-  test('MustacheEngine has the correct extension', () {
-    expect(MustacheEngine.ext, '.mustache');
-  });
-
-  test('MustacheEngine handles reading a file correctly', () async {
-    final filePath = './views/index.mustache';
-    dynamic error;
-    String rendered;
-
-    dynamic callback(dynamic err, String string) {
-      error = err;
-      rendered = string;
-    }
-
-    final mockFileRepository = MockFileRepository();
-
-    when(mockFileRepository.readAsString(Uri.file(filePath)))
-        .thenAnswer((_) async => mockMustache);
-
-    await MustacheEngine.handler(filePath, {}, callback, mockFileRepository);
-
-    expect(error, null);
-    expect(rendered, contains('<html>'));
-    expect(rendered, contains('Hello, World'));
-  });
-
-  test('MustacheEngine handles passing locals into template', () async {
-    final filePath = './views/index.mustache';
-    dynamic error;
-    String rendered;
-
-    dynamic callback(dynamic err, String string) {
-      error = err;
-      rendered = string;
-    }
-
-    final mockFileRepository = MockFileRepository();
-
-    when(mockFileRepository.readAsString(Uri.file(filePath)))
-        .thenAnswer((_) async => mockMustache);
-
-    await MustacheEngine.handler(
-        filePath, {'first_name': 'Devin'}, callback, mockFileRepository);
-
-    expect(error, null);
-    expect(rendered, contains('<html>'));
-    expect(rendered, contains('Hello, Devin'));
-  });
-
-  test('MustacheEngine handles exceptions', () async {
-    final filePath = './views/index.mustache';
-    dynamic error;
-    String rendered;
-
-    dynamic callback(dynamic err, String string) {
-      error = err;
-      rendered = string;
-    }
-
-    final mockFileRepository = MockFileRepository();
-
-    when(mockFileRepository.readAsString(Uri.file(filePath)))
-        .thenThrow(FileSystemException('Could not find file'));
-
-    await MustacheEngine.handler(
-        filePath, {'first_name': 'Devin'}, callback, mockFileRepository);
-
-    expect(error, isA<FileSystemException>());
-    expect((error as FileSystemException).message, 'Could not find file');
-    expect(rendered, null);
-  });
-}